Figure 4. IL-6 and LPS predispose IgM⁺ B cells to calcium mobilization after BCR cross-liking.

Spleen leukocytes were incubated with IL-6 (200 ng/ml), LPS (100 μg/ml) or control media alone for 24, 48 and 72 h at 20 °C. After the different incubation periods, cells were loaded with Fluo-3 AM (5 μM final concentration), and its baseline emission was measured by flow cytometry for 30 s, and then stimulated with 0.5 ug/ml of Alexa 647 conjugated anti-IgM mAb. Fluorescence was then measured for a further 180 s. (a) Mean fluorescence intensity (MFI) plus standard deviation of intracellular Ca²⁺ levels (Fluo-3) in IgM⁺ B cells is shown (n = 6). *P < 0.05, **P < 0.01, ***P < 0.001. (b) Scatter plot showing Fluo-3 MFI levels in spleen IgM⁺ B cells after 48 h of incubation with the appropriate stimuli.